Informações sobre o equipamento:

HP Model 4935A is a Transmission Impairment Measuring
Set (TIMS) which measures wideband data and voice impairments.
The frequency range over which measurements are made
is 20 Hz to 110 kHz, in steps of 1, 10, 100, 1000, or 10,000 Hz
There are four permanently stored, fixed frequencies
404, 1004, 2804. and 2713 Hz. Any other four frequencies
may be temporarily assigned and stored by the user.